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Help: Light and C02 injection


4 Jun 2020
Hi Guys,

Wondering if someone can help me.

I've ordered a custom aquarium (30CM cube), and it will come with x2 4 watt LED lights.

Firstly could someone advise what category of plants this will be sufficient for? I was planning to keep low/medium light plants but don't want Monte Carlo to suffer if the lighting isn't sufficient. Ideally I'd like to keep some carpeting plants with small leaves.

If the lighting is only adequate for easy plants and not strong enough for the 'medium' category plants on the Tropica website for example), then would it still be worth adding pressurised C02?

Hope this makes sense but happy to clarify if needed.

Thanks a lot!


31 Oct 2007
My understanding is 15w of LED is “high light” for a 30cm (e.g. the ADA Aquasky 301, ONF flat nano). Therefore 8w would be “medium light” - a sweet spot: you can probably grow Tropica easy and medium plants with CO2 but it’s not so bright that the slightest error ends in disaster.
My reference is I have a 25cm cube with low light - I’m running a 15w ONF flat nano on it at 25% power with no added carbon. When I turned it up to 50% (roughly what you have) I had major leaf melt on my Staurogyne and Crypts. With CO2 however, that would have been fine.


24 Dec 2014
would it still be worth adding pressurised C02?
Plants will always benefit from some added CO2, but many plants will adapt to non-CO2 (enriched) aquariums as well

When looking at Tropica website, it lists CO2 requirement as low, medium, high
Some of the “easy” plants may still prefer medium CO2 so it’s worth taking note of that detail

Hemianthus micranthemoides makes Tropica’s advancesd category but in local tap (very soft, acidic) water it’s extremely tolerant, though growth will differ as light becomes very shaded and nonCO2

MC is much more tolerant than HC, not just in growth preferences but also trimming (and remaining rooted!)

Iain Sutherland’s Taiwan Bee not so nano is a wonderful journal of a nonCO2 scape

Simon Cole

25 Dec 2018
When I turned it up to 50% (roughly what you have) I had major leaf melt on my Staurogyne and Crypts
Very interesting Ray. I have been looking to find examples of where dimming helps plants to cope.

@kishan313 Alto is right. I tend to find that the leaves on MC will be a lot smaller under reduced light and carbon dioxide levels. It will look about the same scale as HC if grown under your conditions without carbon dioxide enrichment. However, it takes a long time to achieve. I think your best option would be a 95g cylinder feeding into an external filter inlet at about one bubble every 5 or 10 seconds. I have done this before and it lasted months. If you can get your carbon dioxide up from 3ppm to 6ppm (which requires very little enrichment) then you could double plant growth. It means a 6 month carpet could be achieve in 3. You don't need to shoot for 20 or 30ppm in my opinion.
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